Contact lenses made from silicone hydrogels are becoming increasingly popular compared to contact lenses made from conventional hydrogel materials, because, like conventional hydrogel lenses, they are comfortable to wear. These contact lenses have the added advantage of having higher oxygen permeability, which is believed to be healthier for the eye. However, contact lenses made from silicone hydrogels often have physical properties that make them more difficult to manufacture. For example, cast-molded silicone hydrogel contact lenses can adhere to the lens molds necessitating complex processes in order to remove the cured lens from its mold without damage. Additionally, silicone hydrogel contact lenses typically need to be extracted in volatile organic solvents in order to achieve acceptable surface wettability. The use of volatile organic solvents in manufacturing presents safety and environmental concerns and adds costs to the manufacturing process.
New methods for manufacturing silicone hydrogel contact lenses that have less complex demolding and delensing requirements compared to prior methods of manufacture are sought. Methods that do not require use of volatile organic solvents to achieve ophthalmically-acceptable surface wettabilities are also desired.
Background publications include U.S. Publ. No. 2008/0001317; U.S. Publ. No. 2009/0200692; U.S. Publ. No. 2013/0106006, U.S. Pat. No. 5,779,943; U.S. Pat. No. 6,310,116; U.S. Pat. No. 6,719,929; U.S. Pat. No. 6,811,805; U.S. Pat. No. 6,890,075; U.S. Pat. No. 7,798,639; U.S. Pat. No. 7,875,660; and U.S. Pat. No. 7,879,267.